With the Basic course, you can download up to five Premium sticker sets at a time.
If you want to use a different sticker set, you need to delete one of your current sets before you can download another.
Note: For the steps to delete a sticker set, see this Help article.
With the Deluxe course, you can download up to 1,000 Premium sticker and emoji sets at a time.
Note: The number of sets you can have will differ depending on how much storage is available on your device.
You can use your downloaded Premium stickers and emoji in chats. If you turn Display suggestions ON in your settings, you can also choose to use Premium stickers and emoji that you haven't downloaded when they appear as suggestions.
For more information about the suggest feature for stickers and emoji, see this Help article.